I'm a bit of an IG noob, and I've had trouble finding examples, particularly recent examples in regard to default column values.
I can set a default value using the Default settings on the column, but only if the item was populated on page render.

If the item was populated after page load, by some dynamic action, the property does not populate the value.

Edit: The p310_item_id has already reached session state. This IG is within an inline popup, where item_id populated when clicking on a row in a classic report listing items for the model on the page.
I've also tried a PL/SQL Expression using :p310_item_id
Is this possible with declarative syntax, or do I need some JS somewhere?
APEX 19.2